In the art of absorbent articles, there is a need for articles with improved body fit. For sanitary napkins in particular, advances in absorbent materials and covers may offer relatively little benefit in actual use if the fluid from the user does not reach the intended intake regions of the article. A significant gap between the body and the intake area of the pad can result in fluid traveling along the body to stain clothing. Further, fluid on the body will not be effectively removed, resulting in a wet, unclean feeling.
Many efforts have been made to improve body fit. Three-dimensional articles have been proposed with fluff pulp, foams or other bulky elements creating a thick central region of the pad designed to fit female anatomy while in use. However, such articles are bulky, resulting in high cost and inconvenience since a relatively small number of articles can be fit into a pad. Further, interviews with women have indicated a preference for articles that appear relatively thin and flat versus three-dimensional xe2x80x9cpre-shapedxe2x80x9d articles. Further, a pre-shaped article having a fixed shape and size may not adapt well to the wide variety of dimensions that exist among females.
Flexure-resistant deformation elements have been used in an attempt to force an absorbent article to fold into a W-shape when compressed laterally. A limitation typically found in this approach is that the deformation elements are located on the garment side of the article, forcing the entire absorbent core to deflect upward and experience a degree of vertical compression which can reduce the void volume in the article as worn. The stiffness required for shaping induced by a garment-side element can also lead to discomfort when worn. Further, the flexure-resistant deformation elements can add to the cost and complexity of the article, often without increasing the absorbent capacity.
Recently, efforts have been made to create channels, especially embossed channels, in a pad to influence the way a pad deforms when compressed by the legs of the wearer, striving to induce an upward buckling of the central portions of the absorbent core to contact the body. However, some of the absorbent core in the central regions of the article may also be deflected downward, away from the body, especially when multilayered absorbent cores are used, and control of the folding mechanism in general is weak when relying on the influence of embossed side channels. In some cases, folding of the central portions of the absorbent core may be downward, away from the body, resulting in inefficient intake.
Further, prior attempts to improve body fit with embossed arcuate lines may adversely affect fluid handling by permitting fluid flow along the embossed lines toward the edges of the article, where leakage may occur. Generally, such arcuate embossments are outwardly concave, with the longitudinal ends of the embossments being near the outer perimeter of the absorbent core and the longitudinal midpoint of the embossments being relatively closer to the longitudinal centerline than the ends of the embossments. Such outwardly concave arcuate lines are believed to be useful in reducing stiffness and improving body fit, but they may provide channels with low absorbency through which fluid can flow from the center of the pad toward the longitudinal sides of the article.
Wings and tabs have also been added to help promote folding of the article in use to direct the central portion toward the body in a W-shaped geometry, but these also do not provide direct control over the folding geometry, especially in the center of the pad. In general, none of these previous efforts have been fully successful in promoting direct contact of the pad with the body under typical conditions of use.
A particular problem with past efforts for improved body fit is that strategies to raise the central portion of the pad in use, such as expanding foams or embossed side channels, tend to be incompatible with the fit requirements for regions of the pad away from the target area. Ideally, an initially flat pad, when laterally compressed in the crotch region, will assume a W-fold geometry in the center of the pad and will cause the back and ends of the pad to curl upward to fit the body or at least will not encourage those regions to move away from the body. But when known pads are laterally compressed in a way to promote a central W-fold, the front and ends of the article do not curl up and the longitudinal sides of the article in the front and the back may curl downward.
What is needed is an improved structure that increases the likelihood of body contact with the intended intake region of the absorbent core, while also providing good fluid handling, leakage protection and comfort.
It has been discovered that an absorbent article can be relatively flat and yet deform when compressed laterally to give good body fit throughout its length, having, for example, a W-fold geometry substantially limited to the crotch region while also inducing longitudinal upward curl in the front and back regions of the absorbent article, thus giving it an excellent geometry for body fit in sanitary napkins, incontinence pads, and other absorbent articles for use on the body. It has also been discovered that crease lines for promoting downward folding coupled with a shaping line (or multiple shaping lines) for promoting upward folding of portions of the absorbent core can be used to achieve good body fit, offering good control over the upward deflection of a central absorbent member in the absorbent core of the article during lateral compression. Further, it has been discovered that a combination of crease lines and a shaping line in an absorbent core can provide improved fluid handling properties and leakage control in addition to assisting the body-fitting function of an absorbent article, particularly when a wicking barrier is used to separate two distinct members of the absorbent core and permit relative motion of the members during compression.
Hence, in one aspect, the present invention resides in an absorbent article having a crotch region and a body side, the absorbent article comprising:
a) a liquid impervious backsheet;
b) a liquid pervious topsheet attached to the backsheet;
c) an absorbent core positioned between the topsheet and the backsheet, the absorbent core comprising an outer absorbent member and a central absorbent member, the outer absorbent member having a width in the crotch region greater than the width of the central absorbent member in the crotch region, the absorbent core further comprising at least two crease lines outside the central absorbent member and a shaping line in the central absorbent member.
In another aspect, the invention resides in an absorbent article, the article having a crotch region, a body side, and a garment side, the absorbent article comprising:
a) a liquid impervious backsheet;
b) a liquid pervious topsheet attached to the backsheet;
c) an absorbent core positioned between the topsheet and the backsheet, the absorbent core comprising an upper layer toward the body side and a lower layer toward the garment side, the upper layer comprising a shaping line and the absorbent core further comprising crease lines substantially not within the upper layer; and
d) a polymeric web disposed between the upper layer and lower layer of the absorbent article.
In another aspect, the invention resides in an absorbent article having a longitudinal direction, a transverse direction, a vertical direction substantially normal to both the longitudinal and transverse directions, and a body side, the absorbent article comprising:
a) an absorbent core having a body side surface, the absorbent core comprising an outer absorbent member having a central void open toward the body side of the article, and a central absorbent member disposed over the central void of the outer absorbent member and extending at least partially into the void, the central absorbent member comprising a shaping line; and
b) a wicking barrier disposed between the outer absorbent member and the central absorbent member, the wicking barrier comprising a vertical component spanning a vertical distance between the outer absorbent member and the central absorbent member.
In still another aspect, the invention resides in an absorbent article with a crotch region, a longitudinal direction, a transverse direction, and a vertical direction substantially normal to both the longitudinal and transverse directions, the absorbent article comprising:
a) an absorbent core having a central absorbent member and an outer shaping member, the central absorbent member comprising a shaping line, the outer shaping member having a central void defined therein for receiving at least a portion of the central absorbent member, whereby an interface is defined between the central absorbent member and the outer shaping member, the interface spanning a vertical distance, and
b) a wicking barrier disposed along the interface between the central absorbent member and the outer absorbent member.